MGS5's trailer moved me, the child soldier thing always tugs on my heartstrings, and no doubt, they'll explore every aspect of it in a comprehensive way.
I always felt MG was an educational game, I learned more about South American politics in Peace Walker than I even got in school, as a kid, MGS1 taught me about nuclear weapons, the Kurds in Afghanistan, the Gulf War, and cloning.
"Yin and Yang are not good and evil. Their unity is good, their struggle is evil"
This topic made me think a bit about Western culture. It's almost sad that it takes a game or a movie to get us to acknowledge very real problems from other parts of the globe. It can be in the news, & the majority have a "oh well, more people in a third world country died - it's just what happens" reaction. But when those events are humanized by an entertainment media, it seems more real & there is a stronger reaction.
While it's sad that it takes a game/movie/whatever to do that, it is nice that something out there makes us remember that these are people & families & not statistics.
It's not just humanitarian issues, either - also academics. Similar to another poster above, I learned more about renaissance Italy from Assassin's Creed than I ever did in school - not sure of that's an intellectual issue with me and those like me, or more of a commentary on our education system in the US (sorry to non-US members if I generalized by saying "Western" earlier).
Just some brief thoughts while we're on the topic (sort of)...